Thursday, January 03, 2008

As it became clear an attacking tiger in a California zoo was able to leap from its cage last week, zookeepers at Lincoln Park Zoo in Chicago removed a few inches of dirt and plants in the bottom of their tigers' moat to make it as deep as it was designed to be.

Just west of the city at Brookfield Zoo, zoo officials took tape measures to their large animal enclosures to reassure visitors -- and themselves -- that all was as safe in the zoo as they thought it was.

In the week since a tiger got out of its habitat at San Francisco Zoo, killing one visitor and badly mauling two others, zoos across the country have reviewed their enclosures for big cats.

The California investigation has centered on the 121/2-foot height of the tigers' moat, more than 2 feet shorter than recommendations, regulators say. On Monday, officials at the Chicago area's two zoos said they, like many other animal parks, have been reviewing the dimensions of their enclosures.

Even inches matter, they say.

The desire to ensure that zoo moats blocking big cats are deep enough has sent zoo officials out with tape measures and blueprints to look anew at their enclosures and the otherwise obscure guidelines for fences provided by the Association of Zoos and Aquariums, the group that accredits zoos across the country.

Association President Jim Maddy, quoted on the group's Web site, said there is no specific height requirement for walls and moats in tiger and other large cat enclosures, beyond that the cats "be secured to prevent unintentional animal egress."

Still, husbandry manuals for the association's tiger species survival plan offer two suggested heights, depending on the type of enclosure: A wall 14 feet high with a 2-foot overhang if the exhibit is enclosed by a fence that can be climbed, or a 15-foot-high wall if the exhibit is enclosed by a moat, zoo officials say.

The only corrective action in the Chicago area after the California incident has been at Lincoln Park Zoo, where the vice president of collections, Robyn Barbiers, said officials had reconsidered dirt and grass planted in the tigers' moat over the years to make the enclosure more natural.

Landscapers since Saturday have shoveled away "a few inches" of dry grass and soil around the edge of the enclosure's moat, returning it to a gravel bottom and blueprint specifications.

The dirt was always less than a foot deep, Barbiers said.

Landscaping or no, the moats in the Chicago-area zoos' big cat enclosures are taller and wider than in San Francisco, and meet or surpass the Association of Zoos and Aquariums' recommendations.

Lincoln Park's exhibit has a space for the cats that is 10 to 12 feet higher than the bottom of its 24-foot-wide moat. The wall on the visitor's side of the moat is 15 feet high -- perhaps a bit taller now that the grass at the bottom has been removed. Visitors are kept well back of the moat's edge by a fence and prickly bushes, so far away, that tigers in the moat can't even see if people are standing there, Barbiers said.

The zoo's Siberian tigers, 10-year-old Molly and 7-year-old Vahzhno, often hop into the moat, but zoo officials believe they've never hopped back up the same way. Instead, they have always exited the moat through a door to a ramp that returns them through a behind-the-scenes enclosure to the viewing area above.

Brookfield's moat is 23 feet wide, and deeper on both sides than Lincoln Park's. The animals' area is nearly 16 feet above the bottom of the moat; visitors stand more than 20 feet above it, their feet about 4 feet higher than the paws of the animals in the enclosure.

"Our tiger exhibit is quite safe," said Brookfield's vice president of animal care, Kim Smith. "We went back in and remeasured everything this weekend, so we would know exactly, because we felt that was prudent."

Likewise, it was "eyeballing" the exhibit in Lincoln Park Zoo -- and the grass in the bottom of the moat -- that led to the decision to re-landscape the tiger enclosure over the weekend, zoo spokesman Jack Wlezien said.

"Any time there's an accident like this in an accredited facility, it hits home. We have sympathy for the staff and certainly the people involved in the accident," Barbiers said.